Mapping the Human Proteome

A comprehensive map of human proteins throughout the body identifies the testes as home to the most unique blend of gene products.

Nov 10, 2014

Jef Akst

FLICKR, KYLE MCDONALDThe Human Protein Atlas (HPA) Program, a nearly decade-long project led by Mathias Uhlén of the Royal Institute of Technology, in Stockholm, this week published 13 million “maps” of human proteins throughout the body. Each map is a visual representation of what proteins are found in which tissues, generated using fluorescently labeled antibodies to some 17,000 of 20,000 known proteins.

“After [the human] genome was mapped 10 years ago, the logical step was to map proteins and figure out where in the human body they are present,” Sanjay Navani, the India site director for HPA, told DNA India. “Forty-eight normal and 20 cancer-based tissues of close to 300 Swedes were extracted from different human organs and stained with [rabbit-produced] antibodies,” he explained, and more than 10 million images of such tissues were taken and studied.

The team has 3,000 more proteins left to map, but the project is already yielding interesting results, the collaborators said. For example, 2,355 of our proteins are expressed in specific organs only. Of all the tissues and organs examined, the testicles get the prize for producing the most unique proteins, including several involved in meiosis. “What’s going on in the testes is unique, as sperm must survive with half the chromosomes and outside the human body,” Uhlén told New Scientist, adding that he suspects something similar is going on during egg production in female fetuses.

Because the atlas also includes 20 types of malignant tumor, The Economist reported, it could help identify proteins involved in cancer. “If it is difficult to find the site of origin of cancer and target medicines, this information will come useful to zero down on treatment methods,” Navani told DNA India.